RESOLVED FIXED199506
[ContentChangeObserver] didFinishTransition triggers a nested style recalc via isConsideredClickable 
https://bugs.webkit.org/show_bug.cgi?id=199506
Summary [ContentChangeObserver] didFinishTransition triggers a nested style recalc vi...
alan
Reported 2019-07-04 16:19:44 PDT
<rdar://problem/52656221>
Attachments
Patch (6.71 KB, patch)
2019-07-04 16:57 PDT, alan 		no flags
DetailsFormatted DiffDiff
Patch (6.65 KB, patch)
2019-07-04 20:54 PDT, alan 		no flags
DetailsFormatted DiffDiff
Patch (6.61 KB, patch)
2019-07-04 21:06 PDT, alan 		no flags
DetailsFormatted DiffDiff
Show Obsolete (2) View All Add attachment proposed patch, testcase, etc.
alan
Comment 1 2019-07-04 16:57:01 PDT
Created attachment 373475 [details] Patch
alan
Comment 2 2019-07-04 20:54:12 PDT
Created attachment 373476 [details] Patch
alan
Comment 3 2019-07-04 21:06:29 PDT
Created attachment 373477 [details] Patch
alan
Comment 4 2019-07-04 21:06:51 PDT
^^more reliable test case
Antti Koivisto
Comment 5 2019-07-04 21:42:04 PDT
Another option would be to add a parameter to willRespondToMouseClickEvents that prevents style update. computeEditability() where the nested recalc is entered already takes such parameter.
alan
Comment 6 2019-07-04 21:50:31 PDT
(In reply to Antti Koivisto from comment #5) > Another option would be to add a parameter to willRespondToMouseClickEvents > that prevents style update. computeEditability() where the nested recalc is > entered already takes such parameter. There's another isConsideredClickable() callsite (which I can't make async) and I was planning to do exactly that in there.
WebKit Commit Bot
Comment 7 2019-07-04 22:44:23 PDT
Comment on attachment 373477 [details] Patch Clearing flags on attachment: 373477 Committed r247147: <https://trac.webkit.org/changeset/247147>
WebKit Commit Bot
Comment 8 2019-07-04 22:44:25 PDT
All reviewed patches have been landed. Closing bug.
Radar WebKit Bug Importer
Comment 9 2019-07-04 22:45:18 PDT
<rdar://problem/52669516>
Ryosuke Niwa
Comment 10 2019-07-05 01:10:27 PDT
(In reply to zalan from comment #6) > (In reply to Antti Koivisto from comment #5) > > Another option would be to add a parameter to willRespondToMouseClickEvents > > that prevents style update. computeEditability() where the nested recalc is > > entered already takes such parameter. > There's another isConsideredClickable() callsite (which I can't make async) > and I was planning to do exactly that in there. Is that guaranteed to be correct? computeEditability needs the up-to-date style. In cases where computeEditability is called and we don't end up updating the style due to this flag, is the style computeEditability uses guaranteed to be up-to-date?
Antti Koivisto
Comment 11 2019-07-05 04:42:43 PDT
Presumably the heuristics would trigger when the style actually changes, if needed.
alan
Comment 12 2019-07-06 06:14:29 PDT
Actually the other callsite is at RenderTreeUpdater::updateElementRenderer() (ContentChangeObserver::StyleChangeScope -> ~StyleChangeScope). I assume by the time we get here all the styles are resolved and it's safe to call computeEditability. Antti?
Ryosuke Niwa
Comment 13 2019-07-08 19:36:41 PDT
(In reply to zalan from comment #12) > Actually the other callsite is at RenderTreeUpdater::updateElementRenderer() > (ContentChangeObserver::StyleChangeScope -> ~StyleChangeScope). I assume by > the time we get here all the styles are resolved and it's safe to call > computeEditability. Antti? Why can't the code in StyleChangeScope::~StyleChangeScope() be pushed as a post style update task??
Antti Koivisto
Comment 14 2019-07-09 05:09:22 PDT
(In reply to zalan from comment #12) > Actually the other callsite is at RenderTreeUpdater::updateElementRenderer() > (ContentChangeObserver::StyleChangeScope -> ~StyleChangeScope). I assume by > the time we get here all the styles are resolved and it's safe to call > computeEditability. Antti? Yes, it should be safe. Style has just been updated by updateElementRenderer when ~StyleChangeScope runs. Cutting close though.
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